Been running Syn3 in al three holes for 75,000 miles. No problems.

 

It is your choice,mine is to use the correct lube for the job.Motor oil is motor oil not gear lube! Good Luck

 

Just so you know, the Mobile 1 15W-50 (silver or gold cap) automotive oil is just as good as the V-Twin oil. It is usually cheaper, too. You can only use it in the engine though since it has friction modifiers.

Yes, but most of the modern SH and SJ oils can actually meet GL1 and sometimes GL2 classifications. From what I've read and seen, Formula+ (HD's gear oil) is equivalent to a GL1, which Mobile 1 V-Twin actually meets despite being a motor oil.

That being said, it is much better to use a quality gear oil in the transmission of a Big Twin. They stand up to the shearing much better than any other type of lubrication.

 

+ 1...But I've neber used the 15W-50. Can't find it around here anyway.

 

M1 VT 20/50
Spectro 75/140 Tranny
HD Formula + Primary

 

Mobil 1 15w50 can be found around here at Pep Boys, Napa Auto and some Walmarts. Walmart used to carry it in gallon jugs dirt cheap(relatively) but now only carry the quarts.

 

Back when Harley started running Syn 3 in all three holes, I thought it was a load of crap and I still think it's a load of crap.

First, it goes against standard practice which has been around for at least the last 50 years. Second, if it was such a great idea, every other auto and motorcycle manufacturer would have already been doing it (as Harley has never really been an innovator or leader in motorcycle technology).

I've run Mobil-1 V-Twin (20W-50) in my engine and primary for a long time with great success. I run Mobil-1 (75W-90) synthetic in my gear box. Right now, the engine has Rotella T 15W-40 in it as a break-in oil. It has almost 1000 miles on the break-in so I'll be changing over to synthetic very soon.

Along those lines, I do have a question. I had an indy shop manager tell me recently that he didn't like using a synthetic oil in the primary. I guess the school of thought is that the synthetic effects how well the clutch discs grab. Has anyone heard of this before? Anyone running synthetic in the engine and tranny and non-synthetic in the primary?

Also, for those of you who run a 20W-50 oil and do a lot of riding in extremely cold conditions, have you ever considered changing to a lighter weight oil in the winter?

Not trying to hijack the thread here. I just didn't want to start yet another thread on oil.

 

Boy, you're going to get more feedback on this than you care for.

In short, there are people that do just what you described. Probably without much incident either, but I've not done studies to back this up.

As others mentioned, there are literally metric ****-tons of oil related posts on this forum. Everyone claims to know the best, people even send off oil for analysis and stuff. It gets kinda deep.

For me, I decided to go Redline. You can't really find on many store shelves, but you can find it online pretty easily.

I ordered the Redline Big Twin kit, and an extra qt of primary fluid, since it calls for 38oz. Includes 20w 50 for the motor, Redline Shockproof for the transmission, and a qt of Primary fluid. Also comes with little stickers, a hat, and a pretty sweet funnel.

http://www.racerpartswholesale.com/p...yclePowerpacks

$90 ain't a bad price for all three holes. Consider the price for the same server at your local dealer....

 

Mobil-1 20W-50 Motorcycle Oil in all three holes. 25,000+ and no issues.

FWIW, Automobiles have been running 10W oil in both automatic and manual gear boxes since 1985 and automatics since the 50's. Look at the API specification NOT the weight of the oil to determine if it is safe to use (or not).

 

That's what I was taught. I run Mobil 1 syn in the engine and Redline Shockproof in the tranny, but I always run regular old dino oil in the primary. I figure there isn't a wrong way or a right way but I do it this way because someone older and wiser than me taught me that way. However, like the man said before, guys using Mobil 1 or HD Syn in all 3 holes are doing just fine. It boils down to personal choice I suppose.